Date: Jul 11, 2014 11:18 PM
Author: alpha041
Subject: union of two path

if we have path1 and path2 defined as below: 
path1=[1,2,4,9]
path2=[1,7,3,9]
how can we create a graph that it's edges are edges in path1 plus edges in path2 ?
edges of such graphs must be {[1,2],[2,4],[4,9],[1,7],[7,3],[3,9]}
thanks all